package com.qlm.tools;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.security.MessageDigest;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;

import com.jfinal.core.Controller;
import com.jfinal.render.Render;

public class MyCaptchaRender extends Render{ 

private static final String[] strArr = {"3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y"};

private static String randomCodeKey = "JFINAL_JLHHWH_Key";
private static boolean caseInsensitive = true;

private int img_width = 85;
private int img_height = 20;
private int img_randNumber = 6;

public MyCaptchaRender() {
}

public MyCaptchaRender(String randomKey) {
   if (randomKey == null || "".equals(randomKey))
       throw new IllegalArgumentException("randomKey can not be blank");
   randomCodeKey = randomKey;
}

public MyCaptchaRender(int width, int height, int count, boolean isCaseInsensitive) {       
   if(width <=0 || height <=0 || count <=0)
   {
       throw new IllegalArgumentException("Image width or height or count must be > 0");
   }
   this.img_width = width;
   this.img_height = height;
   this.img_randNumber = count;
   caseInsensitive = isCaseInsensitive;
}

public MyCaptchaRender(String randomKey,int width, int height, int count, boolean isCaseInsensitive) {
   if (randomKey == null || "".equals(randomKey))
       throw new IllegalArgumentException("randomKey can not be blank");
   randomCodeKey = randomKey;
    
   if(width <=0 || height <=0 || count <=0)
   {
       throw new IllegalArgumentException("Image width or height or count must be > 0");
   }
   this.img_width = width;
   this.img_height = height;
   this.img_randNumber = count;
   caseInsensitive = isCaseInsensitive;
}

public void render() {
   BufferedImage image = new BufferedImage(img_width, img_height, BufferedImage.TYPE_INT_RGB);
   String vCode = drawGraphic(image);
   vCode = encrypt(vCode);
   Cookie cookie = new Cookie(randomCodeKey, vCode);
   cookie.setMaxAge(-1);
   cookie.setPath("/");
   response.addCookie(cookie);
   response.setHeader("Pragma","no-cache");
   response.setHeader("Cache-Control","no-cache");
   response.setDateHeader("Expires", 0);
   response.setContentType("image/jpeg");
    
   ServletOutputStream sos = null;
   try {
       sos = response.getOutputStream();
       ImageIO.write(image, "jpeg",sos);
   } catch (Exception e) {
       throw new RuntimeException(e);
   }
   finally {
       if (sos != null)
           try {sos.close();} catch (IOException e) {e.printStackTrace();}
   }
}

private String drawGraphic(BufferedImage image){
   // 获取图形上下文
   Graphics g = image.createGraphics();
   // 生成随机类
   Random random = new Random();
   // 设定背景色
   g.setColor(getRandColor(200, 250));
   g.fillRect(0, 0, img_width, img_height);
   // 设定字体
   g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

   // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
   g.setColor(getRandColor(160, 200));
   for (int i = 0; i < 155; i++) {
       int x = random.nextInt(img_width);
       int y = random.nextInt(img_height);
       int xl = random.nextInt(12);
       int yl = random.nextInt(12);
       g.drawLine(x, y, x + xl, y + yl);
   }

   // 取随机产生的认证码(img_randNumber位数字)
   String sRand = "";
   for (int i = 0; i < img_randNumber; i++) {
       String rand = String.valueOf(strArr[random.nextInt(strArr.length)]);
       sRand += rand;
       // 将认证码显示到图象中
       g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
       // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
       g.drawString(rand, 20 * i + 14, 24);
   }

   // 图象生效
   g.dispose();
    
   return sRand;
}

/*
* 给定范围获得随机颜色
*/
private Color getRandColor(int fc, int bc) {
   Random random = new Random();
   if (fc > 255)
       fc = 255;
   if (bc > 255)
       bc = 255;
   int r = fc + random.nextInt(bc - fc);
   int g = fc + random.nextInt(bc - fc);
   int b = fc + random.nextInt(bc - fc);
   return new Color(r, g, b);
}

private static final String encrypt(String srcStr) {
   try {
       String result = "";
       MessageDigest md = MessageDigest.getInstance("MD5");
       byte[] bytes = md.digest(srcStr.getBytes("utf-8"));
       for(byte b:bytes){
           String hex = Integer.toHexString(b&0xFF).toUpperCase();
           result += ((hex.length() ==1 ) ? "0" : "") + hex;
       }
       return result;
   } catch (Exception e) {
       throw new RuntimeException(e);
   }
}

public static boolean validate(Controller controller, String inputRandomCode) {
   if (inputRandomCode == null || "".equals(inputRandomCode))
       return false;
   try {
       if(caseInsensitive)
           inputRandomCode = inputRandomCode.toUpperCase();
       inputRandomCode = encrypt(inputRandomCode);
       return inputRandomCode.equals(controller.getCookie(randomCodeKey));
   } catch (Exception e) {
       e.printStackTrace();
       return false;
   }
}
}
